Remote Hot Phosphoric Acid Sampling for Precise Etch Control
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Solution Overview
Problem
In semiconductor manufacturing, precise control of silicon concentration in hot phosphoric acid is crucial for etching processes, as excessive or insufficient silicon can affect etch rates, leading to inefficiencies or damage during nitride film etching, and existing methods lack efficient automated systems for remote sampling and analysis.
Innovation Solution
A remote sampling system with a holding loop and transfer line connects a sampling site to a centralized analyzer, enabling automatic sampling and analysis of hot phosphoric acid, using remote dilution or thermally-controlled transfer to maintain sample integrity and facilitate precise concentration determination, allowing for feedback control of etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual sampling and analysis methods are used for hot phosphoric acid, then operational flexibility is maintained, but measurement precision and productivity are insufficient
Solution Approach 1:
The system performs preliminary actions by automatically collecting samples from the hot phosphoric acid bath, transporting them through a cooled transfer line, and preparing them for analysis before the actual measurement occurs. This includes automated sampling valve operation, sample pumping, and temperature control during transfer, all occurring before the sample reaches the analysis instrument.
Solution Approach 2:
The patent introduces several intermediary elements: a transfer line that mediates sample transport between the hot acid environment and the analysis instrument, a cooling system that mediates temperature reduction of the sample, and an automated valve system that mediates sample collection and routing. These intermediaries enable precise measurement while maintaining high productivity.
2Productivity
If remote sampling systems are implemented, then productivity and measurement precision improve, but device complexity increases
Solution Approach 1:
The automated sampling system integrates multiple functions into a unified remote sampling platform that can collect samples from different locations, control temperature during transfer, route samples through valves, and prepare them for analysis. This multi-functional design improves productivity while managing complexity through consolidation rather than separate dedicated components for each function.
Solution Approach 2:
The patent replaces manual mechanical sampling operations with an automated system that uses electronically controlled valves, pumps, and temperature control mechanisms. This substitution of manual mechanical actions with automated control systems increases productivity while the modular design manages the resulting complexity.
3Loss of time
If hot phosphoric acid is sampled and transported, then real-time analysis capability is achieved, but sample integrity may be compromised due to temperature control requirements
Solution Approach 1:
The system changes the temperature parameter of the sample during transport by cooling it from the high temperature of the acid bath to a lower temperature suitable for analysis. This parameter change is controlled and monitored to maintain sample integrity while enabling timely analysis. The transfer line temperature control systematically adjusts this parameter.
Solution Approach 2:
The cooled transfer line acts as an intermediary that mediates between the hot acid bath environment and the analysis instrument. It provides a controlled thermal environment during sample transport, protecting sample integrity while enabling rapid transfer. The cooling system serves as another intermediary that manages temperature without compromising the chemical integrity of the sample.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system enables accurate determination of chemical element concentrations in hot phosphoric acid, allowing for precise control of semiconductor processes, ensuring optimal etch rates and preventing damage, thereby improving process efficiency and product quality.
Implementation Method 1
a sample pump at the second location configured to introduce the sample from the holding loop into the transfer line for analysis by the analysis device
Implementation Method 2
ICP spectrometry employs electromagnetically generated partially ionized argon plasma which reaches a temperature of approximately 7,000K. When a sample is introduced to the plasma, the high temperature causes sample atoms to become ionized or emit light.
Implementation Method 3
the high temperature causes sample atoms to become ionized or emit light
Implementation Method 4
the high temperature causes sample atoms to become ionized or emit light. Since each chemical element produces a characteristic mass or emission spectrum, measuring the spectra of the emitted mass or light allows the determination of the elemental composition
Data Source
AI summary
Systems and methods for automatic sampling of a sample for the determination of chemical element concentrations and control of semiconductor processes are described. A system embodiment includes a remote sampling system configured to collect a sample of phosphoric acid at a first location, the remote sampling system including a remote valve having a holding loop coupled thereto; and an analysis system configured for positioning at a second location remote from the first location, the analysis system coupled to the remote valve via a transfer line, the analysis system including an analysis device configured to determine a concentration of one or more components of the sample of phosphoric acid and including a sample pump at the second location configured to introduce the sample from the holding loop into the transfer line for analysis by the analysis device.